Gastric Bypass in a Patient with Unsuspected Malrotation of the Colon

Congenital rotational GI tract abnormalities result from non-rotation or incomplete rotation around the superior mesenteric artery. The incidence is approximately 1 in 500 live births and up to 25% of patients will present in adulthood. If a patient with an unknown rotational GI tract abnormality presents for bypass surgery, there is an increased risk of incorrectly identifying the anatomy and constructing a “Roux-en-O” where an antiperistaltic biliary limb is inadvertently constructed. If this occurs, it leads to functional obstruction, bilious vomiting and eventually death. There are currently no published reports of a Roux-en-Y bypass performed in a patient with malrotation.

This video summarizes a case of an otherwise healthy 21 year old female who presented for laparoscopic gastric bypass. At the beginning of the case, we attempted to identify the ligament of Treitz in the left upper quadrant, however we were surprised to find the terminal ileum and the appendix. This made us suspicious of malrotation and therefore, to avoid the complication of construction of a Roux-en-O, we ran the small bowel starting at the terminal ileum and then identified the ligament of Trietz in the right upper quadrant. Once we had clarified the anatomy, we completed the bypass procedure. In addition, we also demonstrate the technique of how Petersen’s space is closed in malrotation to avoid the risk of internal hernia.

The patient had an uncomplicated post-operative course and was discharged two days following the procedure. This case emphasizes the importance of correctly identifying the ligament of Trietz and highlights the risk of inadvertent construction of a Roux-en-O in a patient who has malrotation of the colon.